1. Field of the Invention
The present invention relates to guidewire introducers and, more particularly, to a quidewire introducer assembly for straightening the J tip of a guidewire.
2. Description of the Prior Art
Guidewires are well known in the prior art. Although employed in a number of contexts, typically they are used to introduce a catheter into a blood vessel. One known procedure generally includes the following steps: 1) inserting a cannula into a blood vessel; 2) feeding a guidewire through the cannula; 3) advancing the guidewire into the blood vessel until the tip of the guidewire is at the desired location; 4) removing the cannula; 5) sliding a catheter over the guidewire and inserting the catheter into the vessel; and 6) withdrawing the guidewire.
Several variations, well known in the art, exist on the above-described procedure. For example, sometimes it is necessary to first insert a guidewire of a particularly small diameter, over which a catheter can be inserted. The first guidewire is then withdrawn and a second guidewire of a larger diameter is inserted into the catheter. The first catheter is withdrawn and a second, larger catheter is inserted over the second, larger guidewire.
Guidewires are typically made from a tightly-wound steel wire of small diameter. Such a construction renders the guidewire sufficiently flexible for its intended use. Further, the guidewires may be of a straight design or may include a J-tip end portion. Guidewires having a straight design generally include a rounded tip portion to prevent the possibility of damaging the blood vessel during the insertion procedure. The coiled construction of such guidewire makes the guidewire susceptible to contamination if it is not handled correctly during an insertion procedure.
In contrast, the distal tip of a J-tip guidewire should not impact the wall of a blood vessel since the advancing portion is in the shape of a "J". Instead, only the gently curved section of the J-tip will contact the walls, thereby facilitating guidewire introduction and reducing the possibility of damaging the blood vessel during insertion thereof.
Since the introduction of J-tip guidewire, several patents have issued disclosing various methods for introducing and placing these guidewire at desired locations within a blood vessel. For example, U.S. Pat. No. 4,405,314 to Cope discloses an apparatus and method for catherization permitting use of a smaller gauge needle. The patent discloses an introducing catheter having a tapered tip which includes a side port such that when a J-tip guidewire is advanced within the catheter, the guidewire will automatically emerge from the side port. The guidewire can then be advanced to the desired location, at which point the introducing catheter is removed and a final catheter is slidably inserted over the J-tip guidewire. U.S Pat. No. 4,552,554 to Gould et al. improves on this apparatus and method for introducing J-tip guidewires. In particular, Gould et al. discloses an introducing catheter that is straight in design, yet still allows a J-tip guidewire to exit from a side port therein. Both of the above mentioned patents require the use of a specially manufactured introducing catheter.